Audiphone-receiver.



(L E. WILLIAMS. AUDIPHONE RECEIVER. APPLICATION FILED JANFB, 1908.

945,429. Patented Jan.4, 1910.

I *cient, there being no room left for a rever- CHARLES E. WILLIAMS,BQSTON, MASSACHUSETTS.

names,

Specification of Letters Patent.

AUDIPHONE-RECEIVER.

Application filed January e, 1908. Serial No. aeaeso.

To all whom it may concern;

Be it knownthat I, CHARLES E. WILLIAMS, a citizen ofthe'United States,and resident of Boston, in the county of Su'lfolk and State ofMassachusetts, have invented an Improvement in Audiphone-Receivers, ofwhich the following description, in connection with the accompanyingdrawings, is a specification, like numerals 0n the drawings representinglike parts. i

Audiphone receivers, as commonly constructed heretofore, have required athick and hence a heavy case to hold andsupport the usual fixed magnet,and as the latter has been in the shape of a thick ring or horseshoe (toleave the necessary space at the center for the electro-magnet) theacoustic properties of the receiver have been incitiberatory chamber,and the permanent magnet and case not only makewthe receiver heavy, butthe necessary location of the former brings it so close to the diaphragmthat the flux of the magnetic field polarizes the diaphragm andseriously interferes with the proper working' of the instrument.

My invention has for its object the elimination of all the foregoingobjectionable features besides introducing various decided advantages.

In accordance with my invention, I provide a more uninterruptedair-space back of the diaphragm, thereby producing a clearer noise andamplifyin the sound more. I secure this space by forming the permanentmagnet. as a part of the case itself, or in other words'l introduceinto' a portion of the case a suitable magnetic material separated fromthe diaphragm by ii. non-mag netic substance, and at the center of thisshell 1 mount the electro-magnet. Preferably this shell or permanentmagnet-case is concavo-convex, being thereby deeper at the center, sothat ltmger cores an be used for the clcctro-magnet without interferingwith the clear space sought for the reverberatory chamber, said longercores allowing of more! turns hf the wire around each core, and aconsequently stronger electro-magnet. Fur thermere by havingthepea'nanent magnet removed, with an intervening revcrberatory chamber,the n-iagnetic field is more even,

and there is much less polarizing ctl'ect on the diaphragm. Thisconstruction also renders it feasible to make the receiver much thinner,and of less diameter, and hence less I conspicuous when on the head, asthe perma;

nent magnet. and hence the case itself, may be cup-shaped. tance is theeconomy of inanufacture and maintenance. I s

In the drawings, in which I have illustrated preferred embodiments of myinvention, Figure 1 is a View in rear elevation of a receiver showingthe magnetic, cup-shaped case; Fig. is a central, transverse sectionalview thereof; Fig. 3 is a top plan view with the cap and diaphragmremoved; Fig. 4 is a view similar to Fig. 2, showing a differentconstruction of electro-niagnet; and Figs. 5 and (5 are similar views offurther modifications.

As the main feature of my invent-ion resides in introducing thepermanent magnet into the case, so that it constitutes a part of theshell or case, and therefore does not consume any of the interior spaceof the receiver, it is evident that it may be embodied in a reat manyconstructions. In the preferred embodimentof the drawings, the case 1consists of a permanent magnet 2 separated from the diaphragm 3 by a rimor ring l of non-magnetic or insulating material, an electro-magnetbeing centrally located within the relatively large and free air-space5,

having its long cores 6, i" secured to the magnetcase 2 at 8 tocooperate with the poles of the latter at the opposite sides of theperiphery of the magnetic portion of the case, and provided with theextra long windings 9, previously mentioned, made possible by theremoval of the usual rings of the permanent magnet from the interior,Another point of impor Patented (tan. a, 1910;

space of the receiver and the cup-shape of the case. The constructionshown is such that all the parts may be light-weight, as

distinguished from the old construction in which a heavy case isrequired to support and secure the heavy permanent magnet, the

latter fills the interior space, shortens the electro-rmignet. andbrings the magnetic field into undue proximity tothediaphra' 1.

In Figs. 5 and (5 l have shown furt ier modifications which come withinmy invention, viewed in its broader aspects, the former figure showingthe permanent magnet at 10 as flat or plane instead of being concavo-convex, and the latter figure also showing the permanent magnet asthin and shelllike in shape. being a thin circular plate, the same as inFig. 5, excepting that instead of being made sulliciently finished to beriveted in position t its edges as the exterior of the retained inposition a thin, non-magnetic backin 112. Also, in order to maintain thelarge ree air space, and at the same time permit the cores of the.electro-malgnet to have the desired extent and contain the long windingspreviously explained, I have extended the cores horizontally, asindicated at '13, with upturned ends 14 and windings 15.

The permanent magnet is thin and shelllike forming an inclosed chamber,outwardly bulging so as to provide a reverberatory cavity or chamber.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is:

i. In an audiphone receiver, a diaphragm, an eleetro-magnct, and a caseof magnetic material extending integrally entirely across the back ofthe receiver, being insulated from the diaphragm and constituting thepermanent magnet of the instrument.

In an audiphone receiver, a diaphragm, an electro-magnet, and a case ofmagnetic material extending integrally entirely across the back of thereceiver, being insulated from the diaphragm and constituting thepermanent magnet of the instrument the cores of the electro-magnet beingmaintained at one end at the opposite sides of the pe riphery of saidmagnetic case.

3. In an audiphone receiver, a diaphragm,

an electro-magnet, and a case of magnetic material insulated from thediaphragm and constituting the permanent magnet of the instrument, thecase having a concav0-c0n vex shape providing a reverberatory' chamberabout the electro-magnet.

4. In an audiphone receiver, a diaphragm, electro-magnet and permanentma net, the latter consisting of a thin circu ar outwardly bulgin plateforming an inclosed chamber and the adjacent core-ends of theelectro-magnet being secured to the diametrically opposite sides of saidplate.

5. In an audiphone receiver, a diaphragm, a permanent magnet having anintegral imperforate back portion at the back of the receiversubstantially coextensive with said diaphragm, said permanent magnetbeing provided with cores extending from adjacent the dian'ietricallyopposite peripheral edges of said integral imperforate back part, andterminating at their free ends adjacent the middle of said diaphragm,and an electromagnet wound in'two parts respectively about saidrespective cores of the permanent magnet.

In testimony whereof, I have signed my name to this specification. inthe presence of two subscribing Witnesses:

CHARLES E. WILLIAMS. W itnesses v M. J. SPALDING, Geo. H. MAXWELL.

